Assess hormonal balance from lab values.
The progesterone-to-estradiol ratio helps assess hormonal balance. Progesterone is converted to pg/mL (×1000) before dividing by estradiol. An optimal ratio of 100–500:1 suggests balanced hormones during the luteal phase. Low ratios may indicate estrogen dominance, associated with PMS, fibrocystic breasts, and endometriosis.